It is highly desirable for silicone protective coatings to provide a durable high gloss finish to surfaces such as auto bodies, vinyl, rubber and leather goods. In combination with these properties, detergent resistance is necessary in order to withstand washings during the normal course of use.
Amine functional silicone coatings commonly used as auto polishes are not corrosion resistant in thin polish films and allow gaseous molecules to penetrate the polymer network.
The salt formed by reaction of alkoxy end blocked amine functional silicones and organic type corrosion inhibitors, such as phenyl stearic acid has been found to provide improved durability to polish formulations. The phenyl stearic acid, silicone amine salt also improves the compatability of silicone fluid with organic waxes (Soap/Cosmetic/Chemical Specialities, July 1971). Examples of alkoxy end blocked organo polysiloxane copolymers including salts of aliphatic carboxylic acids are disclosed in the U.S. Pat. Nos. 3,544,498 to Holdstock et al, issued Dec. 1, 1970 and 3,576,779 to Holdstock et al, issued Apr. 27, 1971. These formulations provided compositions of improved detergent resistancy. Other detergent resistant polish compositions include an alkoxy end blocked amino functional silicone fluid combined with a hydroxyl terminated group polysiloxane and/or silicone resins. An example of this composition is disclosed in the U.S. Pat. No. 3,960,575 to Martin, issued June 1, 1976.
Through continued use, it has been found that these prior art protective coatings lack a combination of good detergent resistance with the other desirable qualities of a protective coating, such as gloss, ease of rub-out, and rust resistance.
The instant invention provides a new composition and method of making the same wherein a trimethyl end blocked polyamine silicone fluid is combined with a fatty acid to derive a polysiloxane fluid including a combination of amide or amine salts and free, unreacted amine alky groups. The resulting polysiloxane copolymer, alone or in combination with other additives, provides improved desirable properties of detergent resistance, gloss, and ease of rub out, in combination with excellent rust resistance characteristics.